I dropped my phone on the concrete. Now, I have a crack and my screen is pitch black. I tried rebooting it and charging it, but it won't come on. I want to know if I can change the screen and if it will come back on or what?
Replacing the screen isn't really a job you can do yourself: it's very fiddly and usually needs special tools. You can take it to a repair shop and they can replace the screen (if they have the replacement screen for your model of phone), but this is usually expensive. Because the screen is one of the most expensive components of the phone, and labour costs are expensive, replacing the screen might cost as much as replacing the whole phone.
You don't know what else might have been damaged by hitting that concrete. If the broken screen is the only damage, then replacing it will make the phone work again. But if the phone's internal components have been damaged too, it may not be possible to replace them. The repair shop should be able to tell you when they've examined the phone.